The aggregation of expert judgment: do good things come to those who weight?

Good policy making should be based on available scientific knowledge. Sometimes this knowledge is well established through research, but often scientists must simply express their judgment, and this is particularly so in risk scenarios that are characterized by high levels of uncertainty. Usually in such cases, the opinions of several experts will be sought in order to pool knowledge and reduce error, raising the question of whether individual expert judgments should be given different weights. We argue--against the commonly advocated "classical method"--that no significant benefits are likely to accrue from unequal weighting in mathematical aggregation. Our argument hinges on the difficulty of constructing reliable and valid measures of substantive expertise upon which to base weights. Practical problems associated with attempts to evaluate experts are also addressed. While our discussion focuses on one specific weighting scheme that is currently gaining in popularity for expert knowledge elicitation, our general thesis applies to externally imposed unequal weighting schemes more generally.

Quality of life in dementia: a systematically conducted narrative review of dementia-specific measurement scales.

OBJECTIVES: Ascertaining the quality of life (QoL) in people with dementia is important for evaluating service outcomes and cost-effectiveness. This paper identifies QoL measures for people with dementia and assesses their properties. METHOD: A systematic narrative review identified articles using dementia QoL measures. Electronic databases searched were AMED, CINAHL, EMBASE, Index to Theses, IBSS, MEDLINE, PsycINFO, Sociological Abstracts, and Web of Science. All available years and languages (if with an English language abstract) were included. RESULTS: Searches yielded 6806 citations; 3043 were multiple duplicates (759 being true duplicates). Abstracts were read; 182 full papers were selected/obtained, of which 126 were included as relevant. Few measures were based on rigorous conceptual frameworks. Some referenced Lawton's model (Dementia Quality of Life [DQOL] and Quality of Life in Alzheimer's Disease [QOL-AD]), though these tapped part of this only; others claimed relationship to a health-related QoL concept (e.g. DEMQOL), though had less social relevance; others were based on limited domains (e.g. activity, affect) or clinical opinions (Quality of Life in Late-Stage Dementia [QUALID]). Many measures were based on proxy assessments or observations of people with dementia's QoL, rather than their own ratings. The Bath Assessment of Subjective Quality of Life in Dementia (BASQID) was developed involving people with dementia and caregivers, but excluded some of their main themes. All measures were tested on selective samples only (ranging from community to hospital clinics, or subsamples/waves of existing population surveys), in a few sites. Their general applicability remains unknown, and predictive validity remains largely untested. CONCLUSION: The lack of consensus on measuring QoL in dementia suggests a need for a broader, more rigorously tested QoL measure.

Salt. UK consumers' perceptions and consumption patterns.

This study investigated UK consumers' perceptions, knowledge and understanding of the salt they consume in their diet and the significance of this for their health. Ten focus groups were conducted in two UK cities (Norwich and London) with a total of 72 participants. Most participants were unaware of the advised salt guidelines (6g per day), or what this equated to within their diet, mainly because they were unclear about how much salt they consumed, given that much is 'hidden' in pre-prepared foods. However, participants were aware of the link between high salt intake and certain negative health associations, though they were unsure about the precise connection. As such, consumption practices were largely driven by habit and lifestyle choices, rather than health considerations. The paper concludes by suggesting that further salt awareness campaigns are needed and that these should be made more relevant to consumers by addressing specific knowledge deficits (such as the presence of 'hidden' salt), although given the intractable nature of human behaviour, more direct efforts to lower salt content (e.g. through manufacturing changes) might be required.

Attitudes and attitudinal ambivalence change towards nanotechnology applied to food production.

The strategic development of novel nanotechnologies will be determined by their public acceptance, which in turn may be influenced by public perceptions of the risks and benefits associated with the specific applications. At the present time, public opinions towards nanotechnologies remain largely inchoate, although this is likely to change with increasing public exposure to relevant information. In two experiments, a total of 618 participants, from the UK population, were provided with different risk-benefit information on nanotechnology application in food. The results show that the provision of both risk and benefit information does not influence average attitude, but results in some individuals becoming more positive and less ambivalent and others more negative and less ambivalent towards nanotechnologies. A third group maintained a neutral attitude and became more ambivalent. It is concluded that to understand public opinion formation about nanotechnology keeping track of polarization and ambivalence is important.

Do treatment preferences for patients with angina change? An 18-month follow-up study.

OBJECTIVES: To assess whether preferences for patients with angina changed at 18-month follow-up using the Patient Preferences Questionnaire for Angina treatment (PPQA). BACKGROUND: Evidence suggests that patients want information about treatment options. Reliable measurement of patient preferences for treatment is important for empowering patients. DESIGN: Postal self-administered questionnaire survey at baseline and follow-up. The preference questionnaire comprised 18 items about the main treatments for angina: medication, angioplasty and coronary artery bypass grafting (CABG). SETTING AND PARTICIPANTS: Patients with diagnosed angina from seven participating general practices across England. The sample comprised 222 patients with angina who responded to both baseline and follow-up treatment preference questionnaires. RESULTS: Most patients' condition and preferences scores for treatment remained stable over 18 months. An exception was angioplasty preference scores, which indicated more negative attitudes towards this procedure over time. People aged over 75 years least preferred angioplasty. There were no associations between any changes in condition and changes in preferences. However, within-subject agreement could vary by ± 5 to 7 points between baseline and follow-up, with stability apparently worst for the medication and best for surgery sub-scales, raising the question of what represents reasonable stability. CONCLUSION: These results suggest preferences are relatively stable, even where there are changes in health, and provide further evidence of the utility (in particular, reliability) of the PPQA. However, this stability in scores did mask some movement in scale scores and in patients' first-ranked treatment choices, showing changing preferences largely from angioplasty to CABG and vice versa, indicating the complexity of preferences.

A study of patient expectations in a Norfolk general practice.

OBJECTIVE: To use semi-structured interviews to ascertain patterns in patients' expectations of health care and the extent to which these expectations were met or not. BACKGROUND: In health policy it is important to evaluate health services from varying perspectives including consumers'. One concept of emerging importance in this regard is that of patient expectations. Whether expectations are met or not have been found to be related to general patient satisfaction with treatment and treatment compliance. However, there is conceptual and methodological uncertainty and little informing empirical work regarding what is an 'expectation' and how it should be measured. DESIGN: A qualitative study using semi-structured interviews to elicit 20 GP patients' expectations prior to their consultation. A post consultation interview gauged the extent to which these expectations had been met. SETTING AND PARTICIPANT: Twenty patients of a GP practice in Norfolk (UK). RESULTS: Results suggest several different expectations, concerned with the doctor-patient interaction, the specific processes of the consultation, outcomes, and issues to do with time and space. CONCLUSIONS: This research has used an innovative exploratory approach to address the expectations of GP patients and has implications for how doctors ought to manage their consultations. These results will be used to inform the development of a quantitative expectations questionnaire so as to develop a validated measure of expectations. Such an instrument has great potential to aid in health care research and practice.

Food allergy: stakeholder perspectives on acceptable risk.

We have reached a point where it is difficult to improve food allergy risk management without an agreement on levels of acceptable risk. This paper presents and discusses the perspectives of the different stakeholders (allergic consumers, health professionals, public authorities and the food industry) on acceptable risk in food allergy. Understanding where these perspectives diverge and even conflict may help develop an approach to define what is acceptable. Uncertainty about food allergy, its consequences and how to manage them is the common denominator of the stakeholders' views. In patients, uncertainty is caused by the unpredictability of reactions and the concern about whether avoidance strategies will be effective enough. Variability of symptoms and the lack of markers do not allow stratification of patients according to their reactivity, and force health professionals to give the same advice to all patients despite the fact that the risk to each is not identical. Regulators and the food industry struggle with the fact that the lack of management thresholds forces them to make case-by-case decisions in an area of uncertainty with penalties for under- or over-prediction. As zero risk is not a realistic possibility, consensus on acceptable risk will be needed.

Public engagement in research funding: a study of public capabilities and engagement methodology.

One trend in public engagement concerns involving the public in research priority setting. In this study members of the public were asked to select which of four potential projects (about food-related topics, presented by scientists) ought to be funded. The aim of the study was twofold: to trial and evaluate a method of engaging with the public about science, and to study the factors used by the public in making funding allocation decisions. Results suggest that, while participants enjoyed the process and appeared to learn from it, they were not particularly "representative"--a common problem with engagement approaches of this type. Results also suggest that participants' funding decisions were largely based on factors such as "benefit to society" and "personal relevance," though aspects such as the "likeability" and "trustworthiness" of the speaker may have played a role. Implications for involving the public in funding policy decisions are discussed.

What do patients really want? Patients' preferences for treatment for angina.

OBJECTIVE: To measure preferences for angina treatments among patients admitted from accident and emergency with acute coronary syndrome. BACKGROUND: Evidence suggests variability in treatment allocations amongst certain socio-demographic groups (e.g. related to age and sex), although it is unclear whether this reflects patient choice, as research on patients' treatment preferences is sparse. Given current policy emphasis on 'patient choice', providers need to anticipate patients' preferences to plan appropriate and acceptable health services. DESIGN: Self-administered questionnaire survey. SETTING: In-patients in a UK hospital. PARTICIPANTS: A convenience sample of 53 newly admitted patients with acute coronary syndrome. Exclusion criteria were: a previous cardiologist consultation (including previous revascularization); a clinical judgement of too ill to participate; post-admission death; non-cardiac reasons for chest pain. MAIN OUTCOME MEASURES: Patients' preferences for coronary artery bypass graft (CABG); angioplasty; and two medication alternatives. RESULTS: Angioplasty was the preferred treatment (for 80% of respondents), and CABG was second (most preferred by 19%, but second most preferred for 60%). The two least preferred (and least acceptable) treatments were medications. The majority of patients (83%) would 'choose treatment based on the extent of benefits' and 'accept any treatment, no matter how extreme, to return to health'. There were some differences in preference related to age (>70 years preferred medication to a greater degree than <70 years) and sex (males preferred CABG surgery more than females). CONCLUSIONS: There was general preference for procedural interventions over medication, but most patients would accept any treatment, however extreme, to return to former health. There was some evidence of differences in preferences related to age and sex. Furthermore, most patients preferred to have some input into treatment choice (e.g. nearly half wanted to share decision responsibility with their doctor), with only 4% preferring to leave the decision entirely to their doctor. Given these findings, and past findings that suggest there may be variability in treatment allocation according to certain socio-demographic factors, this study suggests a need to develop and use preference measures, and makes a step towards this.

Patient preferences for treatment for angina: an overview of findings from three studies.

BACKGROUND: Access to cardiac treatments has been documented to vary with patients' age. It is unknown whether these variations reflect patients' treatment preferences. We aimed to investigate patients' preferences for cardiology treatments and develop a Patients' Preferences Questionnaire. METHODS: Semi-structured interviews with primary care patients with diagnosed angina with postal follow-up. The resulting Patients' Preferences Questionnaire was tested with newly admitted inpatients with acute coronary syndrome and with patients in primary care. RESULTS: The Patients' Preferences Questionnaire was psychometrically sound. Analyses of preference subscale scores showed that the most positive preference scores were for medication. Angioplasty scored highest at the negative end of the scale. Detailed analyses showed that older people and women were less likely to prefer coronary artery bypass surgery (CABG), reflecting its greater level of invasiveness. Older people (aged over 75 years, compared to people aged under 75 years), but not women, were also more cautious in their strength of preference for angioplasty. More positive attitudes towards CABG surgery, and more negative attitudes towards medication, were associated with greater impact of the condition on life. CONCLUSIONS: The research resulted in a psychometrically sound Patients' Preferences Questionnaire. There was some evidence to support the view that older people's weaker preferences for CABG may contribute slightly to variations in the provision of re-vascularization. There was also variation in preferences within age groups, cautioning against the assumption that all or most older people are more reluctant than younger people to undergo invasive procedures.

Assessing patients' preferences for treatments for angina using a modified repertory grid method.

A current popular theme in medicine concerns whether and how patients should be involved in treatment choice. Assuming patient involvement is desirable, how should one go about eliciting preferences? A variety of quantitative and qualitative methods exist that may be used for this purpose, one of which is the repertory grid method. This method involves eliciting constructs (reasons) for preferences through comparing sets of three options. This method allows the structured elicitation of the reasons behind individual preferences, but also, when used with generalised procrustes analysis (GPA), allows aggregation of individual data to reveal general preference patterns. In this study the repertory grid method was used to examine patient preferences for angina treatments with the goal of, first, gaining some understanding of general patterns of patient preference, and second, examining the likely utility of the technique in this setting. A sample of 21 patients with mild and stable angina from two general practices in Norfolk, UK was interviewed using the repertory grid method to elicit the constructs underlying their preferences amongst seven angina treatments (including 'no treatment'). Individualised questionnaires were then produced and sent to the patients for self-completion, which required rating the extent to which each construct was relevant for each treatment (scored on visual analogue rating scales). Analysis of the ratings, using GPA, showed that the constructs clustered around two dimensions: 'some treatment' versus 'no treatment', and drug treatment versus surgical treatment. While some treatment was generally preferred to no treatment, individuals varied in preference for drug treatments or surgical treatments. Although the latter were generally perceived as 'effective' they were also perceived, for example, as 'invasive', 'frightening', related to 'negative experiences', and being more appropriate for when symptoms are severe ('proportionate'). We consider the implications of these results for involving patients in choosing amongst treatments.

How can genetically modified foods be made publicly acceptable?

A recent study by Lusk suggests that consumers might voluntarily pay more for a genetically modified (GM) food than a non-GM equivalent if made aware of the possible health benefits. However, other research indicates that the acceptability of novel hazards is affected by a variety of factors, in addition to benefits, and that making agricultural biotechnology publicly acceptable will be more complex than indicated by the results from Lusk's study.

Characteristics of the peanut chain in Europe - implications for peanut allergy.

BACKGROUND: Peanuts are one of the main food allergens, occasionally responsible for life-threatening reactions. Thus, many studies have tried to fi nd a connection between peanut allergy prevalence and processes in the peanut chain that may contribute to the peanut allergenicity. To inform this discussion, this paper outlines experiences in peanut cultivation, trade and processing in Europe, focusing on four European countries with different peanut experiences (Poland, Bulgaria, Spain and the UK). MATERIAL AND METHOD: Results here are based on documentary analysis and semi-structured, face-to-face interviews with 32 experts involved in various stages of the peanut chain, including peanut farmers, processors, traders, food technologists and manufacturers. RESULTS: A common peanut chain diagram has been drawn considering shelled and in-shell peanuts. The analysis of each stage of peanut processing has been made in accordance with this peanut chain schema. Thermal and mechanical processes are discussed alongside the resultant end peanut products available for European consumers. The paper also analyses the main trends of peanut trade in Europe. The results suggest that the majority of peanut products in Europe are roasted, implying enhanced exposure of the population to more allergenic peanuts. CONCLUSION: The presented schema and related discussion bring together diverse aspects of peanut production, trade and processing. The main factor associated with the increased allergenicity of peanuts appears to be high temperature roasting. Frying and boiling are also thermal processes, but fried and boiled peanuts have been associated with reduce peanut allergenicity. Neither country of origin nor cultivar type appear to be related to differential peanut allergenicity. More research is needed as regards the impact of various additives, such as chocolate (which is also considered an allergen) on the allergenicity of peanut products. The use of peanuts in non-food products also needs more investigation.

Patients' experiences of their healthcare in relation to their expectations and satisfaction: a population survey.

OBJECTIVES: To investigate patients' experiences of health services, and how these related to what they had expected to receive, and satisfaction with their care. DESIGN: Surveys of patients before and after their consultations in general practice and hospital outpatients departments. SETTING: Greater London and Essex PARTICIPANTS: In total, 833 patients attending 21 hospitals (434 patients; 52%) and 22 general practices (399 patients; 49%) across Greater London and Essex sampled in clinics and a population survey. MAIN OUTCOME MEASURES: Patient expectations of care, patient satisfaction. RESULTS: Compared with younger people, and those in black and ethnic minority groups, older people (aged 65+) and White British people had significantly higher overall realistic expectations of their care (pre-visit realistic expectations score: age 60+: mean 53.26 [standard deviation 13.73]; age <60: 56.20 [15.17]; White British: 54.41 [13.50]; Black and other ethnic groups: 56.90 [16.15]) and greater satisfaction post-consultation (satisfaction score age 60+: 1.71 [0.80]; age <60: 1.97 [0.97]; White British: 1.79 [0.89]; Black and other ethnic groups: 2.01 [0.95]). Pre-visit ideal and realistic expectations of care was not significantly associated with patient satisfaction, although met expectations (post-visit experiences) were. Elements of these which was predictive of satisfaction were communication with the doctor, information conveyed and clinical outcomes. Factors associated with satisfaction included having a sense of control over one's life, being older, female, White British and attending general practice, compared with hospital outpatient clinics. CONCLUSIONS: It is the ability of the system to meet patients' expectations in respect of the emotional and human features of the consultation, and the clinical outcomes, that matter most to people. This research also questions prevailing stereotypes of older age: it is not the case that older patients are more satisfied with their care because their expectations are lower. In fact, they are higher, but they believe that they are being met.

Consumer responses to communication about food risk management.

Recent emphasis within policy circles has been on transparent communication with consumers about food risk management decisions and practices. As a consequence, it is important to develop best practice regarding communication with the public about how food risks are managed. In the current study, the provision of information about regulatory enforcement, proactive risk management, scientific uncertainty and risk variability were manipulated in an experiment designed to examine their impact on consumer perceptions of food risk management quality. In order to compare consumer reactions across different cases, three food hazards were selected (mycotoxins on organically grown food, pesticide residues, and a genetically modified potato). Data were collected from representative samples of consumers in Germany, Greece, Norway and the UK. Scores on the "perceived food risk management quality" scale were subjected to a repeated-measures mixed linear model. Analysis points to a number of important findings, including the existence of cultural variation regarding the impact of risk communication strategies-something which has obvious implications for pan-European risk communication approaches. For example, while communication of uncertainty had a positive impact in Germany, it had a negative impact in the UK and Norway. Results also indicate that food risk managers should inform the public about enforcement of safety laws when communicating scientific uncertainty associated with risks. This has implications for the coordination of risk communication strategies between risk assessment and risk management organizations.

Perceptions of food risk management among key stakeholders: results from a cross-European study.

In designing and implementing appropriate food risk management strategies, it is important to examine how key stakeholders perceive both the practice and effectiveness of food risk management. The objective of this study is to identify similarities and differences in perceptions of, and attitudes to, food risk management practices held by consumers and experts with an interest in food safety. Focus groups were conducted in five European countries chosen for their (hypothesised) cultural differences in attitudes towards risk: Denmark, Germany, Greece, Slovenia and the UK. Content analysis was carried out on the resulting texts and (sub) categories were identified within the analysis framework to facilitate the capture of emerging themes. Five key themes were identified as common to the perceptions of both consumers and experts, although these are not represented in the same way by both groups. These key themes are: (1) efforts made by the responsible authorities to manage food risks; (2) responsibility for prevention and management of food risks; (3) how priorities are established within regulatory systems; (4) scientific progress and its implications for food risk management; and (5) media attention and food safety incidents. Although some similarities emerged between the groups, differences were also identified. For example, experts appeared to be highly negative about media influences, whereas consumers appeared more indifferent about media influences and motives. These different perspectives need to be addressed in order to reduce the perceptual distance between key stakeholders, and in particular, to enhance consumer confidence in the food risk management system. Based on the study findings, recommendations for food risk management policies are outlined.